1. Field of the Invention
This invention relates generally to data processing systems and, more particularly, to data processing systems in which a plurality of processing units store data elements in a common main memory unit.
2. Description of the Related Art
In data processing systems in which a plurality of data processing units share a main memory unit for storing data required by the processing unit, a control program is implemented to share equitably the resources including the main memory among a multiplicity of users while simultaneously maintaining the integrity of data elements from inadvertent or malicious compromise. The control program can be in simultaneous execution in a plurality of data processing units. Therefore, the control program must synchronize the access to the data elements that are used to control the allocation and protection of resources. A similar problem can be present for users of the data processing system if their programs are executed on several data processing units simultaneously, referred to as parallel processing or multithreading.
A need has therefore been felt for a flexible and efficient technique whereby changes in the data elements stored in main memory can be synchronized, thereby maintaining data integrity.